Generally, a battery that cannot again be used once discharged is called a primary battery, and a battery that may be reused after being discharged is called a secondary battery.
Recently, with the increase in the supply of portable devices such as feature phones, smart phones, Personal Digital Assistant (PDA) phones and digital cameras, the demand for secondary batteries is increasing rapidly. Secondary batteries used for portable devices require high-stability and a thin profile for convenient carrying as well as a long life that can be maintained after a short charging time.
A Constant Current mode-Constant Voltage mode charge method (CC-CV charge method) is generally used as a method for charging secondary batteries used for portable devices In charging the secondary batteries, the CC-CV charge method is one that performs charge with a certain constant current and thereafter charges the secondary battery with a constant voltage when a voltage close to a full-charge potential is reached.
Research on various charge methods that may perform more accurate full charge and perform charge at a faster charge speed than the CC-CV charge method is being conducted.
Furthermore, as the supply of various portable devices having a large consumption power increases rapidly, interest in batteries is increasing. Accordingly, a charge method and a charge apparatus are required which are more stable and may become fully charged in a shorter amount of time.